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suricata/src/detect-decode-event.c

313 lines
7.5 KiB
C

/** Copyright (c) 2009 Open Information Security Foundation
*
* \author Breno Silva <breno.silva@gmail.com>
*/
#include "suricata-common.h"
#include "suricata.h"
#include "decode.h"
#include "detect.h"
#include "flow-var.h"
#include "decode-events.h"
/* Need to get the DEvents[] array */
#define DETECT_EVENTS
#include "detect-decode-event.h"
#include "util-unittest.h"
#define PARSE_REGEX "\\S[0-9A-z_]+[.][A-z+]+$"
static pcre *parse_regex;
static pcre_extra *parse_regex_study;
int DetectDecodeEventMatch (ThreadVars *, DetectEngineThreadCtx *, Packet *, Signature *, SigMatch *);
int DetectDecodeEventSetup (DetectEngineCtx *, Signature *s, SigMatch *m, char *str);
void DecodeEventRegisterTests(void);
/**
* \brief Registration function for decode-event: keyword
*/
void DetectDecodeEventRegister (void) {
sigmatch_table[DETECT_DECODE_EVENT].name = "decode-event";
sigmatch_table[DETECT_DECODE_EVENT].Match = DetectDecodeEventMatch;
sigmatch_table[DETECT_DECODE_EVENT].Setup = DetectDecodeEventSetup;
sigmatch_table[DETECT_DECODE_EVENT].Free = NULL;
sigmatch_table[DETECT_DECODE_EVENT].RegisterTests = DecodeEventRegisterTests;
const char *eb;
int eo;
int opts = 0;
parse_regex = pcre_compile(PARSE_REGEX, opts, &eb, &eo, NULL);
if(parse_regex == NULL)
{
printf("pcre compile of \"%s\" failed at offset %" PRId32 ": %s\n", PARSE_REGEX, eo, eb);
goto error;
}
parse_regex_study = pcre_study(parse_regex, 0, &eb);
if(eb != NULL)
{
printf("pcre study failed: %s\n", eb);
goto error;
}
return;
error:
return;
}
/**
* \brief This function is used to match decoder event flags set on a packet with those passed via decode-event:
*
* \param t pointer to thread vars
* \param det_ctx pointer to the pattern matcher thread
* \param p pointer to the current packet
* \param s pointer to the Signature
* \param m pointer to the sigmatch
*
* \retval 0 no match
* \retval 1 match
*/
int DetectDecodeEventMatch (ThreadVars *t, DetectEngineThreadCtx *det_ctx, Packet *p, Signature *s, SigMatch *m)
{
int ret = 0;
DetectDecodeEventData *de = (DetectDecodeEventData *)m->ctx;
if(de && DECODER_ISSET_EVENT(p, de->event))
return 1;
return ret;
}
/**
* \brief This function is used to parse decoder events options passed via decode-event: keyword
*
* \param rawstr Pointer to the user provided decode-event options
*
* \retval de pointer to DetectFlowData on success
* \retval NULL on failure
*/
DetectDecodeEventData *DetectDecodeEventParse (char *rawstr)
{
int i;
DetectDecodeEventData *de = NULL;
#define MAX_SUBSTRINGS 30
int ret = 0, res = 0, found = 0;
int ov[MAX_SUBSTRINGS];
ret = pcre_exec(parse_regex, parse_regex_study, rawstr, strlen(rawstr), 0, 0, ov, MAX_SUBSTRINGS);
if (ret < 1) {
goto error;
}
const char *str_ptr;
res = pcre_get_substring((char *)rawstr, ov, MAX_SUBSTRINGS, 0, &str_ptr);
if (res < 0) {
goto error;
}
for(i = 0; DEvents[i].event_name != NULL; i++) {
if((strncasecmp(DEvents[i].event_name,str_ptr,strlen(DEvents[i].event_name))) == 0) {
found = 1;
break;
}
}
if(found == 0)
goto error;
de = malloc(sizeof(DetectDecodeEventData));
if (de == NULL) {
printf("DetectDecodeEventSetup malloc failed\n");
goto error;
}
de->event = DEvents[i].code;
return de;
error:
if (de) free(de);
return NULL;
}
/**
* \brief this function is used to add the parsed decode-event into the current signature
*
* \param de_ctx pointer to the Detection Engine Context
* \param s pointer to the Current Signature
* \param m pointer to the Current SigMatch
* \param rawstr pointer to the user provided decode-event options
*
* \retval 0 on Success
* \retval -1 on Failure
*/
int DetectDecodeEventSetup (DetectEngineCtx *de_ctx, Signature *s, SigMatch *m, char *rawstr)
{
DetectDecodeEventData *de = NULL;
SigMatch *sm = NULL;
de = DetectDecodeEventParse(rawstr);
if (de == NULL)
goto error;
sm = SigMatchAlloc();
if (sm == NULL)
goto error;
sm->type = DETECT_DECODE_EVENT;
sm->ctx = (void *)de;
SigMatchAppend(s,m,sm);
return 0;
error:
if (de) free(de);
if (sm) free(sm);
return -1;
}
/**
* \brief this function will free memory associated with DetectDecodeEventData
*
* \param de pointer to DetectDecodeEventData
*/
void DetectDecodeEventFree(DetectDecodeEventData *de) {
if(de) free(de);
}
/*
* ONLY TESTS BELOW THIS COMMENT
*/
#ifdef UNITTESTS
/**
* \test DecodeEventTestParse01 is a test for a valid decode-event value
*/
int DecodeEventTestParse01 (void) {
DetectDecodeEventData *de = NULL;
de = DetectDecodeEventParse("ipv4.pkt_too_small");
if (de) {
DetectDecodeEventFree(de);
return 1;
}
return 0;
}
/**
* \test DecodeEventTestParse02 is a test for a valid upper + lower case decode-event value
*/
int DecodeEventTestParse02 (void) {
DetectDecodeEventData *de = NULL;
de = DetectDecodeEventParse("PPP.pkt_too_small");
if (de) {
DetectDecodeEventFree(de);
return 1;
}
return 0;
}
/**
* \test DecodeEventTestParse03 is a test for a valid upper case decode-event value
*/
int DecodeEventTestParse03 (void) {
DetectDecodeEventData *de = NULL;
de = DetectDecodeEventParse("IPV6.PKT_TOO_SMALL");
if (de) {
DetectDecodeEventFree(de);
return 1;
}
return 0;
}
/**
* \test DecodeEventTestParse04 is a test for an invalid upper case decode-event value
*/
int DecodeEventTestParse04 (void) {
DetectDecodeEventData *de = NULL;
de = DetectDecodeEventParse("IPV6.INVALID_EVENT");
if (de) {
DetectDecodeEventFree(de);
return 1;
}
return 0;
}
/**
* \test DecodeEventTestParse05 is a test for an invalid char into the decode-event value
*/
int DecodeEventTestParse05 (void) {
DetectDecodeEventData *de = NULL;
de = DetectDecodeEventParse("IPV-6,INVALID_CHAR");
if (de) {
DetectDecodeEventFree(de);
return 1;
}
return 0;
}
/**
* \test DecodeEventTestParse06 is a test for match function with valid decode-event value
*/
int DecodeEventTestParse06 (void) {
Packet p;
ThreadVars tv;
int ret = 0;
DetectDecodeEventData *de = NULL;
SigMatch *sm = NULL;
memset(&tv, 0, sizeof(ThreadVars));
memset(&p, 0, sizeof(Packet));
DECODER_SET_EVENT(&p,PPP_PKT_TOO_SMALL);
de = DetectDecodeEventParse("ppp.pkt_too_small");
if (de == NULL)
goto error;
de->event = PPP_PKT_TOO_SMALL;
sm = SigMatchAlloc();
if (sm == NULL)
goto error;
sm->type = DETECT_DECODE_EVENT;
sm->ctx = (void *)de;
ret = DetectDecodeEventMatch(&tv,NULL,&p,NULL,sm);
if(ret)
return 1;
error:
if (de) free(de);
if (sm) free(sm);
return 0;
}
#endif /* UNITTESTS */
/**
* \brief this function registers unit tests for DecodeEvent
*/
void DecodeEventRegisterTests(void) {
#ifdef UNITTESTS
UtRegisterTest("DecodeEventTestParse01", DecodeEventTestParse01, 1);
UtRegisterTest("DecodeEventTestParse02", DecodeEventTestParse02, 1);
UtRegisterTest("DecodeEventTestParse03", DecodeEventTestParse03, 1);
UtRegisterTest("DecodeEventTestParse04", DecodeEventTestParse04, 0);
UtRegisterTest("DecodeEventTestParse05", DecodeEventTestParse05, 0);
UtRegisterTest("DecodeEventTestParse06", DecodeEventTestParse06, 1);
#endif /* UNITTESTS */
}